PROJECT SUMMARY/ABSTRACT Zika virus (ZIKV) is an emerging mosquito-borne virus that is causing explosive outbreaks. While asymptomatic in most healthy adults, ZIKV infection of pregnant women causes severe developmental complications of fetuses, including fetal death, microcephaly and a variety of other neurological complications. No animal model of fetal ZIKV infection is currently available. Because adult rhesus macaques can be infected with Zika virus, including isolates from recent outbreaks, it is important to investigate if ZIKV infection of fetal macaques has similar detrimental effects. The development of a nonhuman primate model of fetal pathogenesis, that affords precise experimental control, is critical to (i) determine the mechanisms of how ZIKV infection affects the developing fetus, including the fetal brain and other parts of the central nervous system, and (ii) to develop and screen intervention strategies, including vaccines and therapeutics. The proposed pilot studies, aimed at demonstrating proof-of-concept, have been designed to test whether ZIKV infection initiated at different times of gestation can recapitulate the spectrum of outcomes described in ZIKV-infected pregnant women, and determine how the timing of ZIKV infection in pregnancy associates with markers of viral replication, viral distribution, immune markers and pathology. The overarching objective of the proposed work is to develop a NHP model of fetal pathogenesis, ultimately allowing scientists to expedite clinical trials with the ultimate goal of curtailing the ZIKV pandemic as quickly as possible.